The exact and correct location of the idle bypass hole in a carburetor relative to the closed throttle plate within the throttle section is a critical dimension to the smooth functioning of the carburetor and the smooth transition of the engine from idle to off-idle operation without hesitation or stumbling.
Heretofore there were a number of tolerance variables which stack up in carburetor constructions, such as diameter of the throttle bore, diameter of the throttle plate, variations of the diameter of the throttle shaft and the hole size in the carburetor body for the throttle shaft, location of the center line of the throttle shaft with respect to the center line of the throttle section. All of these variables tended to produce malfunctioning of the carburetor due to a variation of this critical distance between the edge of the throttle plate where it engages the throttle section on its periphery and the location of the adjacent idle bypass hole.
Heretofore there has long existed the problem of assuring in advance that this critical dimension and location of the idle bypass hole as it is machined through the carburetor body upstream of the throttle plate is such as to produce a smooth function of the carburetor and a smooth transition of the engine from idle to off-idle operation without hesitation of stumbling.
Various efforts have heretofore been made in determining the correct location of the idle bypass hole so as to achieve a correct critical distance and specific location for the cutting axis of a laser drilling unit or cutting tool normally extending at right angles to the longitudinal axis of the carburetor body.